Remote control system



June 20, 1939. I s w. L Y 2,163,411

REMOTE CONTROL SYSTEM Filed Oct. 28, 1937 3 Sheets-Sheet l 130 422 21 INVENTOR STU/127' m 515) ATTORNEY J1me 1939- s. w. SEELEY ,163,411

REMOTE CONTROL SYSTEM Filed Oct. 28, 1937 3 Sheets-Sheet 2 INVENTOR 7 371/427 Ell-V '7 BY Wag- ATTORNEY June 20, 1939. s w SEELEY 2,163,411

' REMOTE CONTROL SYSTEM Filed Oct. 28, 1937 3 Sheets-Sheet 3 INVENTOR STUART W. S ELF) ATTO R N EY e y, N. at, to Radio America, a corpora-t Dela- Appiication @ctoher 28, H37; Seriai No. 171,486

The present invention relates to remote control devices and more particularly to arrangements for remotely controlling the rotation of a shaft which, for instance, may be the tuning shaft of a radio receiver or the rotating means of the volume control device.

A feature of the invention is that the controlling action is obtained by producing impulses at the remote point, transmitting these impulses to the controlled point and utilizing the received impulses to operate a step by step mechanism.

A particularly important feature of a modification of .the invention is that the circuit arrangements are such that no standby power is used.

Still another feature of the invention is the use of a power supply network for transmitting the controlling impulses.

Other features of the invention will be apparent from a reading of the following detailed specification in conjunction with the drawings, wherein Figure 1 illustrates in schematic form a possible arrangement of a remote control unit incorporating the features of the invention;

Figure 2 illustrates a controlled unit utilizing gas tubes; and,

Figure 3 illustrates a controlled unit utilizing ordinary electronic tubes. i

Referring to Figure 1 of the drawings, conductors 41 and 48 represent the power supply network as usually found in all buildings provided with electric light and power supply. Tubes H5 and H5 are oscillator tubes provided with input and output circuits coupled together for producing oscillations. The tank circuit or frequency determining circuit of tube I I5 includes the inductance coil I21 shunted by the condenser Ill while the tank or frequency determining circuit of tube I I9 comprises the inductance coil I25 shunted by the tuning condenser I26. Connection is made between the anode of tube H5 and the upper terminal of coil I21 through the conductor H3. The grid of tube *I I5 is connected to the lower terminal of coil I21 through a condenser H2. The output circuit of tube H5 is completed by connecting an intermediate point of coil I21 to the cathode of the tube through.a condenser I28. A grid leak resistor IIB provides a direct current connection between the cathode and grid of the tube. It can be seen that due to the connection of the cathode to an intermediate point of coil I21 through the condenser I28, the anode circuit of tube H5 is regeneratively coupled to the grid circuit thereof and the degree of coupling is such that oscillations of a frequency determined by the tank circuit 52?, H4 are generated when the proper potentials are applied to the various electrodes of the tube. Plate potential for the tube 585 is supplied through a power transformer I06, the secondary E? of which is tapped at its mid point by connection thereto of a conductor I00.

In the case of tube II9 the anode thereof is connected to the lower end of coil I25 by means of a conductor I20 while the upper end of the coil is connected to the grid of the tube through a coupling condenser I2I. A grid leak is provided between the grid and cathode of tube II9 by connecting between these two elements a resistor II8. The anode circuit 'of tube H9 is completed by means of the connection of a condenser I29 between an intermediate point of coil I25 and the cathode of the tube. It should be noted that the grid-cathode connections of both tubes H5 and I I9 have a, common portion I I! which is grounded as at G. The anode and grid circuits of tube I I9 are coupled together as in the case of tube I I5 to produce regeneration and, hence, the generation of oscillations, the frequency of which is determined by the tuning of the tank circuit I25, I26. In the case here being considered both tubes are arranged so as to generate oscillations of the same frequency. The output of tube I I 5 is fed to the power supply line 41-48 by means of a circuit comprising conductor I09, coil I II, condenser H0 and switch I02. Conductor 48 is connected to ground through condenser I03, so as to provide the return circuit to the cathode of tube I i5. In the same way the output .of tube H9 is transferred to the power supply line 01-48 through the coupling circuit comprising conductor I22, coil I23,'ccndenser I24, conductor I09, switch I02 to the power supply line conductor 41. Here again, the return circuit is through ground by connection of the power supply line conductor 48 to ground through the condenser I03 and the connection of the cathode of tube II9 to ground.

Power supply for the tubes H5 and H9 is obtained by connecting the power transformer I06 to the power supply line 41-48. The transformer I06 comprises a primary I05 and a tapped secondary ")1 which acts as a push-pull transformer in that the anodesof tubes H5 and H9 are alternately positive and negative with 180 degrees phase difference between them. Thus, when the anode of tube H5 is positive, the anode of tube II 9 is necessarily negative and vice versa. Since oscillations areg enerated only when the anode of a particular tube is positive with respect to its cathode, the oscillations are generated alternatesence of force.

1y by the two tubes. The anode potential is supplied to the anode of tube II5 through the connection of the upper terminal of secondary I01 to the intermediate point of the coil I21. This connection is through a switch device I43I44 so that no plate voltage is supplied to the anodeof tube I I5 when this switch is open. In the drawing the switch is shown open. Anode potential for the tube H9 is supplied by connection of the lower end of the lever device is provided with a depending portion I40 which is constructed of suitable insulation material on which the contact elements I42 and I43 are supported and insulated from each other.

The upper end of the device I36 is provided with a turned-out and downwardly projecting portion including a pointer I45. Suitably mounted behind the pointer I45 on the lever I36 there is provided a spring switch comprising spring element I41 and contact element I48. The bias on the spring element I41 is such as to maintain the spring contact open in the ab- To close the contact there is provided a cam follower I49 which is mounted on the underside of the spring element I41. This cam follower is arranged so as to ride on the cam surface I35 of a disc-like device I34 fixed to the shaft I39. It can be seen from the drawing that by grasping the knob I 46 which is attached to the element I36 for providing a convenient way of rotating element I36 about the shaft I39, the switch I41-I48 will be alternately closed and opened as the'cam follower I49 rides over the high and low portions of the cam surface I35. The contact device I48 is connected by means of a conductor I08 to the tapped point of the secondary I01 while the switch element I41 is grounded at G. In reality the circuit including the conductor I08 and switch 'I41I48 comprises the cathode return circuit for the two tubes 5 and 9 so that if the switch device I41--I48 is open no anode voltage is supplied to either one of the tubes irrespective of the condition of switches I4I--I42 and I43I44. Switch elements I and I44 are fixed to the surface of a disc I31 which is also rotatably supported by the shaft I39 adjacent to the device I36. The arrangement is such that when a. force is applied to handle I46 so as to turn the device I36 clockwise, a certain amount of free motion is provided between device I36 and disc I31 until the contact device I42 comes in contact with the switch element I. When this happens further clockwise movement of I36 carries with it the disc I31 in the same direction.

It follows at once that if a force is applied to the handle I46 tending to rotate the device I36 counter-clockwise, the depending portion I40 will move over counter-clockwise until contact I43 comes in contact with I44 at which time further counter-clockwise movement of device I36 carries with it the disc I31 thereby rotating it in a counter-clockwise direction. The device provides an arrangement for energizing either tube H5 or tube H9 in accordance with the direction in which the lever device I36 is operated. Thus,

. oscillator tubes.

if lever I36 is operated in a clockwise direction closure of switch I4II42 completes the circuit between the lower terminal of the secondary I01 and the intermediate point of coil I25. However, this alone is not sufflcient to energize the tube I I9 since it.is also necessary to have a return circuit from the cathode of the tube to the midpoint of secondary I01. This return circuit is established only upon closure of switch I41-I48. -In this way oscillations are generated by the tube II9 only when the lever device I36 is moved in a clockwise direction, the number of impulses depends upon the number of times the cam follower I49 rides over a high portion of the cam surface I35. Thus by movement of lever device I36 clockwise a series of impulses are generated by tube II9, the number of these series being determined by the number of high portions of the cam surface I36 traversed in moving the lever device from the starting position to the stopping position. It is, of course, apparent that movement of the lever device I36 counter-clockwise will of the power transformer I06, the impulses providedby tube 5 are out of phase with the impulses provided by the tube H9. The impulses lmpressed upon the power supply line 41, 48 are the controlling impulses which are utilized at the controlled point to operate the step by step mechanism. I

Considering the remote control unit in another way, it will be seen that the oscillations generated'by the tubes H5 and H9 may be considered as being modulated by the 60 cycle alternating current available across the power supply lines 41 and 48 when such is provided by the power supply network. This modulation is due to the rise and fall as well as the reversal of the 60 cycle potentials applied to the anodes of the The modulation components so produced contain a predominant 60 cycle characteristic. It, therefore, may be considered that movement of the lever device I36 in one direction as compared to movement thereof in y the other direction produces a 180 phase change in the 60 cycle modulation component of the oscillations put on to the power supply network. To take advantage of the phase change, there are provided two controlled circuits at the controlled point of the network, each of which incorporates a three element gas tube of the type described in copending application Serial No;

suitable catch mechanisms I0 and 9 which are 75 ivoted respectively at 38 and i5. The catch mechanism 58 is pivotally supported by pin it within a slot formed near the upper end of the plunger device ii. The lower end of the catch device i i is provided with a slot l8 which is adapted to receive .a pin 59 mounted within the slot 22 so as to limit the movement of the catch device. A spring ll biases the catch device l4 so as to tend to rotate the device about its pivot it in a clockwise manner. The plunger 3 is operated by means of an electromagnet d which is connected through conductors 25 and it and transformer 28 to the power supply circuit 47, 38.

It should be noted that the primary 39 of transformer 28 has one side connected to power supply conductor 38 through conductor 6% while the other side of the primary 3d is connected to the power supply conductor 47 by means of a switch 35-38 and conductors 43 and 49. In this way no operating current is supplied to the primary it of transformer 28 unless the switch 35, St is closed. The electromagnet and plunger arrangement 6 and t is arranged so that when the electromagnet 6 is energized the plunger 8 is pulled downwardly, thereby advancing the disc 3 a predetermined amount clockwise. Suitable stops, (not shown) are provided so as to limit the motion of plunger 8 in either direction. The plunger 8 is biased by a suitable spring (not shown) so that when the electromagnet 6 is deenergized, as when switch 35-36 is open, the spring acts to return the plunger 8 to its normal released position which is that shown. In the same way the plunger I is operated by the electromagnet through connection thereof to the power supply line 41, 48 through transformer 27 and switch 33-34. However, in this case the operation of the plunger 1 operates the disc 4 and thereby turns shaft 2 in the opposite direction, that is, counter-clockwise.

It should be noted that when the plungers 'l and 8 are in the released position, that is, when the operating electromagnets 5 and B are deenergized, the catches l3 and I4 are forced into their respective slots 2I and 22 by means of projections I50 and I5! over which theouter edge of the catches I3 and I4 respectively must ride. The purpose of the stops is to prevent locking the wheels 4 and 3 when the electromagnets 5 and 6 are deenergized. Projections I50 and I5! are suitable mounted on the framework of the unit (not shown).

The switch 33.34 is operated'by means of a relay winding 39 which is controlled by a three element gas tube 50. Switch 35, 36 on the other hand, is controlled by relay winding 40 which in turn is controlled by the three element gas tube 6|. Gas tubes such as ill and GI have been described more fully in mysaid copending ap plication and as a matter of fact, tubes 60 and BI are connected to the power supply network 41 and 48 in the same manner as the connections of tubes 24 and 34 to the network I and 2 of my said copending application. Since the output of either tube H5 or tube H9 (see Figure 1) is impressed upon the power supply network 41, 48 at the remote point it travels through the network and may be received at the controlled point. The tubes 60 and GI are connected to the network in such a way that one of these tubes operates when the lever device I36 is moved in one direction and the other of the three element gas tubes operates when the lever device I36 is movedin the opposite direction in a. manner as described in my said copending application. As a conse- QJWSAEI g upon wl is re a. Since ti e i i-'5 causes impulses to r relay er electro we 2, t

nected to the contactor alternating current from work down plunger and t shaft 2 countei cloclrv se. pulse ceases, spring wiil to between elements 3:3, ing electromagnet and allo spring (not shown) to return in the place of the gang condenser unit so as to be operated by rotation of the shaft 2.

The arrangement shown in Figure 2 due to the use or gas tubes has the advantage that no power is used during standby periods. Thus, in tuning a radio, for instance, it is only necessary to plug in a control device such as shown in Figure i into the power supply network, close the switch i8 2 and then operate the lever device Hi; to tune to any desired station. Tubes 8% and 69, as described in my said copending application, are always ready to operate when the controlled unit is connected to a power line, even though no power is being utilized by them until the receipt of the proper controlling impulse. It may be sometimesdesirable to utilize ordinary electronic tubes at the controlled point. In such a case standby power may also be zero if a gas tube controlled from the remote point is used to connect these tubes to the power supply line in the manner described in my said copending application. In such a system no standby power is used by the electronic tubes until a controlling impulse operates the gas tube and thereby connects these electronic tubes to the power supply line by operating a switch in the same manner as described in my said copending application, it being noted, for instance, that a device such as shown in Figure 3 may be connected to the power supply lines through a terminal 29 shown in Figure 2 of my said copending application.

Referring now to Figure 3 of the present application, the transformers 21 and 28 are the same as transformers 21 and 28 shown in Figure 2 and these act to energize the electromagnets 5 and 6 and, hence, operate the shaft 2. Everything above the transformers 21 and 28 has been omitted in order to simplify the discussion but it is to be understood that a similar arrangement as shown in Figure 2 may be connected. The} arrangement of the tubes 83, 84 and 96 in Figure 3 is essentially-the same as the arrangement of tubes 24 and 23 of Figure 1 of my copending application Serial No. 168,180 filed October 9, 1937, so that the arrangement including tubes 83 and 34 acts as a phase detector circuit in that. the excitation of either tube 83 or tube 84 depends 5 upon the phase of .the incoming envelope of the ,radio frequency voltage which is transmitted from the remote point by means of the arrange ment shown in Figure 1. Alternating current is impressed on th two anodes of tubes 83 and 84 in push-pull from a center tap power transformer l'l. Sensitive low current relays 38 and 48 which operate switches 33-34 and 35-36 respectively are connected in the anode circuits of the two tubes 83 and 84. 60 cycle alternating current voltage is also supplied to the control grids of tubes 83 and 84 .in push-pull through the transformer 89 and the magnitude and phase of this voltage is so arranged as to maintain the two tubes in an inoperative condition, that is, no

plate current flows in either tube. The purpose of resistors RI and R2 is to cause self-rectifica tion during the positive excursions of the A. C. grid voltage with respect to cathode in the tubes. The resistors limit the flow of grid current which 5 otherwise would be abnormal when the grid is positive and the plate negative with respect to the cathode. The radio frequency impulses are utilized in the following manner:

Radio frequency is taken from the line 43, 44 which in turn is connected to the network 41, 48

through circuit 98-99 which constitutes a coupling coil and condenser arrangement. The condenser acts to-block out the 60 cycle line voltage. The radio frequency voltage is transferred to coil 81 and is increased in amplitude by resonant rise in circuit 85, 91 which is resonated at the carrier frequency generated at the remote point. The envelope of the radio frequency voltage is thus extracted by means'of the detector tube 98 as 40 described in my copending application Serial No. 168,180 and the envelope appears across resistor 93. 'Since this resistor is in the common portion of the push-pull input circuit of tubes 83 and 84 the envelope voltage is applied to the 5 two grids of tubes 83'and 84 in parallel, that is, in like manner. Which one of the tubes 83, 84 passes anode current is determined by the phase relation between the alternating current plate potential as applied through transformer 11 and the radio frequency envelope. That one of the tubes 83 and 84, whose plate is at its peak positive ;value with respect to cathode will pass current when the radio frequency envelope is similarly at its peak positive value wtih respect to I cathode. Reversal of the phase of the envelope will cause the other tube to pass plate current.

In order to prevent chattering of the relays 39 and 38 by-pass condenser 19 and 88 are provided to thereby by-pass the alternating current com- 0 ponent of the anode current of the tubes.

Springs 31 and 38 are attached to the framework at one end thereof and to the movable elements 36 and 48 of the relays in order to maintain the switches open when the relays are deenergized.

It is to be understood that the present invention is not to be limited to the embodiment illustrated, but is to be limited only by the appended claims.

I claim:

1. In a system for controlling the operation of a shaft from a remote point by means of a step by step mechanism which is arranged to be responsive to electrical impulses, an electrical cir- 75 cuit connected between the remote point and the control point, means at the remote point for generating oscillations including a selectively operable interrupting device, said means acting upon selective operation to produce electrical impulses, means for impressing the produced electrical im- 5 pulses upon the electrical circuit to transmit the sameto the controlled point, a relay circuit at the controlled point for operating the step by step mechanism, said relay circuit including a gas tube permanently connected to the electrical circuit and acting upon receipt of the transmitted impulses at the controlled point to'cause the energization of the relay with each received impulse and thereby operate the step by step mechanism.

2. In a remote control system including a relay 15 operated step by step mechanism, arranged to be controlled over an electric light and power supply line from a point along the line which is remote therefrom, a gas tube connected across the supply line, said gas tube being characterized by 20 that the supply line potential normally applied across it is insufficient to cause the same to break down and pass current, means for connecting said relay to the gas tube whereby the relay is ener-' gized by current passing through. the tube, a controlling means coupled to the line at the remote point and comprising oscillation generating means and a selectively operable interrupting means, said controlling means acting upon selective operation thereof to produce electrical im- 30 pulses, means for impressing the produced electrical impulses upon the supply line whereby they are impressed upon the gas tube, said electrical impulses causing potentials to be applied to the gas tube which-cause the tube to break down 3! and thereby energize the relay each time an impulse is impressed upon the power supply line. 3. In a remote control system operation over an alternating current power supply line said system being of the type utilizing a step by step mechanism which is operated by an electric driving means, switching means for connecting the driving means to the power supply line to energize the same, relay meansfor operating said switch ing means, a gas tube connected to the power supply line, means for applying a potential derived from the power supply line to the tube, said potential being insuflicient to cause the tube to break down and pass current, means for connecting the relay means to the gas tube so that 50 when the tube breaks down and passes currentthe relay means becomes energized thereby operating the switching means and thereby connect the driving means to the power supply line, a controlling means adapted to be connected to the power supply line, said controlling means including selectively operable means for generating radio frequency electric control impulses, means for impressing the generated impulses upon the power supply line whereby the same are impressed upon said gas tube, said impulses causing potentials to be impressed upon the gas tube which when added 'to the potential normally applied thereto cause the tube to break down and pass current with each impressed impulse.

4. In a remote control system operative over an electric light and power supply line, a pair of electrical driving means, individual switching means for connecting the driving means to the power supply line to energize the same, means for controlling the operation of one of said switching means comprising a first gas tube connected across the power supply line and arranged to derive from the power supply line a potential which is slightly below the potential necessary to cause a,1es,41 the tube to break down and pass current. a second gas tube similarly connected to the power supply line and arranged to control the operation of the other switching means, means for coupling said last named means to the power supply line including a selectiyely operable interrupting device acting upon selective operation to determine the frequency of the generated oscillations and the number of impulses thereof impressed upon the power supply circuit and means interposed between the power supply circuit and the first gas tube for impressing upon the first gas tube impulse impressed upon the power supply line of one oi said frequencies whereby the potential of said impulses is added to the normal power supply iine potential applied to the first tube to.

cause the same to break down and pass current and means interposed between the power supply line and the second gas tube for applying to the second gas tube impulses of another of said frequencies whereby the potential of said impulses is added with the normal power supply line potential applied to said tube to cause the same to break down and pass current.

STUART W. SEELEY. 

